<?php
class page{
    private $page;//当前页数
    private $pagenum;//每一页显示的数量
    private $totalnum;//总记录数
    private $totalpage;//总页数
    private $sql;

    function __construct($sql,$pagenum,$page) {
        $this->sql=$sql;
        $this->pagenum=$pagenum;
        $this->page=$page;
    }
    //获取记录
    function getPage(){
        global $mysqli;
//        0,6 1
//        6,6 2
//        12,6 3
        $result=$mysqli->query($this->sql);
        $this->totalnum=$result->num_rows;
        $this->totalpage= ceil($this->totalnum/$this->pagenum);//获取总页数 向上取整
        if($this->page<=0)
        {
            $this->page=1;
        }
        $startnum = ($this->page-1)*$this->pagenum;
        $this->sql.=" limit $startnum,$this->pagenum";
        $result=$mysqli->query($this->sql);
        return $result;
    }

    //获取总记录数

//    function getTotalNum(){
//       global $mysqli;
//      $result=$mysqli->query($this->sql);
//      return $result->num_rows;
//    }
    function getList(){
        //当总记录数小于等于每页显示的记录
        if($this->totalnum<=$this->pagenum)
        {
            echo "总记录数：$this->totalnum";
        }
        //当总记录数大于每页显示的记录
        else{
            $prev= $this->page-1;
            //5页>=5页
            //当前页面大于等于总页数
            if($this->page>=$this->totalpage){
                $next=$this->totalpage; //当前页面等于总页面数
            }
            //当前页面小于总页数1<2
            else{
                $next= $this->page+1;
            }
            echo "<a href='?page=1'>首页</a><a href='?page= $prev'>上一页</a>";
            //如果总页数小于7页
            if($this->totalpage<=7)
            {   //如果当前页面等于循环中的$i 高亮显示
                for($i=1;$i<=$this->totalpage;$i++)
                {
                    if($this->page==$i)
                    {
                        echo "<a href='?page=$i' class='on'>$i</a> ";
                    }
                    else{
                        echo "<a href='?page=$i'>$i</a> ";
                    }
                }
            }
            else{
                if($this->page==1 || $this->page==2 || $this->page==3)
                {
                    $b=1;
                    $m=7;
                }
                if($this->page>3)
                {
                    $b= $this->page-3;
                    $m= $this->page+3;
                }
                if($this->page==$this->totalpage || $this->page==$this->totalpage-1 || $this->page==$this->totalpage-2)
                {
                    $b=$this->totalpage-6;
                    $m= $this->totalpage;
                }
                if($this->page>4)
                {
                    echo "...";
                }
                for($i=$b;$i<=$m;$i++){
                    if($this->page==$i)
                    {
                        echo "<a href='?page=$i' class='on'>$i</a> ";
                    }
                    else{
                        echo "<a href='?page=$i'>$i</a> ";
                    }
                }
                if($this->page<$this->totalpage-3)
                {
                    echo "...";
                }
            }
            echo "<a href='?page=$next'>下一页</a><a href='?page= $this->totalpage'>末页</a>";
        }
    }
}